Vascular Surgery - Toronto Notes Flashcards
A hypercoagulable state predisposes you to peripheral arterial disease. What are the causes of this state?
- Congenital
- Group I (reduced anticoagulants)
- Antithrombin
- Protein C
- Protein S
- Group II (increased coagulants)
- Factor V Leiden
- Prothrombin
- Factor VIII
- Hyper-homocysteinemia
- Group I (reduced anticoagulants)
- Acquired
- Immobility
- Cancer
- Pregnancy
- Antiphospholipid antibody syndrome
- Inflammatory disorders
- Myeloproliferative disorders
- Nephrotic syndrome
- DIC
- Heparin Induced Thrombocytopenia (HIT)
What investigations would you choose to do to investigate peripheral vascular disease?
- History and physical exam
- Depending on degree of ischemia mayhave to forgeo investigations and go straight to operating room
- Ankle brachial pressure index
- ECG
- tropoin - rule out recent MI or arrythmia
- FBC
- rule out leukocytosis, thrombocytosis or recent drop in platelets in patients receiving heparin
- PT/INR
- patient anticoagulated/sub-therapeutic INR
- Echocardiogram
- Identify wall motion abnormalities, intracardiac thrombus, valvular disease, aortic dissection (type A)
- Ultrasound duplex with doppler
- CT Angiogram
- Underlying atherosclerosis, aneurysm, aortic dissection
What are the differences between arterial embolism and thrombosis?
Embolus:
- Acute
- Prominent loss of function
- No History of claudication
- No atrophic changes
- Contralateral limb pulses are classically normal
Thrombus
- Progressive onset
- Less profound loss of function due to underlying collateral supply
- Maybe claudication
- Maybe atrophic changes
- Decreased or absent contralateral limb pulses
Name two complications of acute arterial occlusion/insufficiency in the lower limbs?
- Compartment syndrome with prolonged ischemia - requiring fasciotomy
- Renal failure and multi-organ failure due to toxic metabolities from ischemic muscle (also known as myoglobinuria due to rhabdomyolysis)
What are the six symptoms of acute limb ischemia?
- Pain - although absent in about 20% of the cases
- Pallor - within a few hours - it becomes mottled cyanosis
- Paresthesia - light touch lost first then sensory modalities
- Paralysis/Power loss - most important - heralds impending gangrene
- Polar - perishingly cold
- Pulselessness - again not reliable
What is your treatment plan for a patient with acute arterial insufficiency?
- Immediate heparinization with bolus and continuous infusion to maintain PTT >60s
- If absent power and sensation - commence emergent revascularization
- If present power and sensation - begin work-up (including angiogram)
- Definitive treatment
- Embolus - embolectomy
- Thrombus - thrombectomy (you can subsequently consider a bypass graft or endovascular therapy)
- Irreversible ischemia - consider primary amputation
- Identify and treat underlying cause
- Continue heparin post-op
- Start warfarin post-op on day 1, 3 times depending on underlying etiology
Name seven risk factors for chronic arterial insufficiency
- Smoking
- Diabetes Mellitus
- Hypertension
- Hyperlipidemia
- Family History
- Obesity
- Sedentary Lifestyle
What are the clinical features seen in claudication?
- Pain with exertion - usually in calves or any exercising muscle group
- Relieved by short rest - 2 to 5 minutes - and no postural changes necessary
- Reproducible - same distance to elicit pain, same location of pain, same amount of rest to relieve pain
What is your differential diagnosis for claudication?
- Vascular
- Atherosclerotic disease
- Vasculitis (e.g. Buerger’s disease, Takayasu’s arteritis)
- Diabetic neuropathy
- Venous disease (DVT, varicose veins)
- Popliteal entrapment syndrome (e.g. Baker’s cyst)
- Neurologic
- Neurospinal disease (spinal stenosis)
- Reflex sympathetic dystrophy
- Musculoskeletal
- Osteoarthritis
- Rheumatoid arthritis/connective tissue disease
- Remote trauma
What are the clinical features in critical limb ischemia?
- Includes rest pain, nocturnal pain, tissue loss (ulceration or gangrene)
- Ankle pressure <40 mmHg, toe pressure <30mmHg, ABPI <0.40
What other clinical signs and symptoms can be seen and elicited in chronic arterial insufficiency?
- Pulses may be absent in some locations
- Bruits may be present
- Signs of poor perfusion
- Hair loss
- Hypertrophic nails
- Atrophic muscle
- Skin ulcerations and infections
- Slow capillary refill
- Prolonged pallor with elevation and rubor on dependency
- Venous troughing ( collapse of superficial veins of foot)
What investigations would you perform in a case of chronic arterial insufficiency?
- Non-invasive
- Routine bloodwork, fasting metabolic profile
- ABPI
- Take highest brachial and highest ankle pressures for each side generally
- CT Angio and MR Angio
- Excellent for large arteries (aorta, iliac, femoral, popliteal) may have difficulty with tibial arteries (especially in presence of disease).
- Both require IV injection of nephrotoxic contrast (iodinated contrast for CT, gadolinium for MR)
- Invasive
- Arteriography - superior resolution to CTA/MRA, better for tibial arteries, can be done intraoperatively
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- Arteriography - superior resolution to CTA/MRA, better for tibial arteries, can be done intraoperatively
What is your treatment plan for chronic arterial insufficiency?
- Conservative
- Risk factor modification
- smoking cessation
- treatment of hypertension
- treatment of hyperlipidemia
- Exercise programe
- improve collateral circulation
- oxygen extraction at the muscle level foot care (especially in DM)
- Keep wounds clean and dry
- Avoid trauma and pressure on wounds
- Risk factor modification
- Pharmacotherapy
- Anti-platelet agents (clopidogrel and then aspirin)
- Cilostazol (c-AMP phosphodiesterase inhibitor with anti-platelet and vasodilatory effects - improves walking distance)
- Surgical/endovascular
- Indicated with severe lifestyle impairment, vocational impairment or critical ischemia
- Options
- endovascular (stenting/angioplasty)
- endarterectomy (removal of plaque and repair with patch - usually distal aorta or common/profunda femoral)
- bypass graft sites
- aortofemora
- axillofemoral
- femoropopliteal
- distal arterial
- Usually choose synthetic polytetrafluoroethylene graft - Dacron
- Chemical sympathectomy
- Amputation
What is an aortic dissection?
A tear in aortic intima allowing blood to dissect into the media, acute is defined as having happened for less than 2 weeks and chronic as greater than 2 weeks.
What is the etiology of aortic dissection?
- Hypertension is the most common
- degenerative/cystic changes to the aortic media
- connective tissue disease (Marfan’s, Ehlres-Danlos)
- cystic medial necrosis
- atherosclerosis
- congenital conditions - coarctation of the aorta
- infection - syphilis
- trauma
- arteritis (Takayasu’s)
Describe the clinical features of an aortic dissection
- HTN (75-85% of patients)
- asymmetric BPs and pulses between arms (>30 mmHg difference indicates poor prognosis)
- ischemic syndromes due to occlusion of aortic branches: coronary (MI), carotids (ischemic stroke, Horner’s syndrome), splanchnic (mesenteric ischemia), renal (AKI), peripheral (ischemic leg), intercostal vessels (spinal cord ischemia)
- “unseating” of aortic valve cusps (new diastolic murmur in 20-30%)
- rupture into pleura (dyspnea, hemoptysis) or peritoneum (hypotension, shock) or pericardium (cardiac tamponade)
- syncope
What investigations would you consider to a suspected case of aortic dissection?
- CXR
- pleural cap (pleural effusion in lung apices)
- widened mediastinum
- left pleural effusion with extravasation of blood
- Transesophgeal echocardiogram
- can visualise aortic valve and thoracic aorta but not abdominal aorta
- ECG
- Any evidence of left ventricular hypertrophy with ischemic changes, perciarditis or heart block
- CT (gold standard), aortography, MRA
- Blood tests
- Lactate in regards to ischemic gut
- Amylase in regards to pancreatitis
- Troponin in regards to myocardial infarction
Outline your course of treatment for an aortic dissection
- Pharmacologic
- beta blockers to lower the blood pressure and decrease cardiac contractility
- use nondihydropyridine calcium channel blocker if there is a clear contraindication to beta blockers
- target systolic blood pressure of 110 mmHg and HR of less than 60 bpm
- Ace-inhibitors or other vasodilators if insufficient BP or HR control
- Surgical
- Resection of segment with intimal tear
- reconstitution of flow through true lumen
- replacement of the affected aorta with prosthetic graft
- corrrection of any predisposing factors